Iron powder composition for gas-cutting, gas-washing, and gas-scarfing



IRON POWDER COMPOSITION FOR GAS-CUT- TING, GAS-WASHING, AND GAS-SCARFINGSeiji Nishikiori, 40 Jiodani, Hinaga, Chita-cho, Chita-gun,

Aichi-ken, Japan, and Yasuharu Okada, 18, 1 Yomeicho, Mizuho-ku,Nagoya-shi, Japan No Drawing. Filed Nov. 28, 1958, Ser. No. 776,707

Claims priority, application Japan Dec. 7, 1957 1 Claim. (Cl. 75--.5)

This invention relates to iron powder and more particularly to the ironpowder which is used for the purpose of gas-cutting, gas-washing, andgas-scarfing, which will hereinafter be called simply gas-cutting.

It has heretofore been conventional to employ pulvertized electric ironor reduced iron powder as metal powder used for gas-cutting purpose.

Although these types of iron powder may well serve the purpose of thegas-cutting of alloy steels such as stainless steel, they can not beapplied to the gas-cutting of cast iron, super heat-resisting alloys,and non-metallic substances like concrete and refractory brick on theground that the heat evolved by the oxidation of the iron powder isinsufiicient to supply the requirements for the gas-cutting of suchtypes of material.

Accordingly, attempts have been made to enhance the oxidation heatrequired for the gas-cutting of such types of material by adding asuitable amount of aluminum powder to the iron powder which is usuallyemployed alone with the gas-cutting. However, uniform mixing of aluminumpowder with iron powder is hardly achieved because of a considerabledifference in their specific gravities, and thus in practice the ratioof these two types of metal powder in the mixture when used varies atall times. Moreover, aluminum powder in a pulverized state is verysusceptible of combustion when exposed to a heating gas flame and isfound as aluminum oxide when brought in contact with the oxyacetylenecutting flame. Consequently the heat given to the cutting surface of theobjective is found scant. Thus, the operation of the gas-cuttingemploying conventional metal powder has been carried out with greatdifficulty at low efliciency resulting in deleterious defects on thesurface cut of the objective. In addition, aluminum powder is costly.

The present invention provides a unique iron powder for gas-cutting useto remove the aforesaid disadvantages incurred in gas-cutting practicewhich employs the existing metal powder.

In the preparation of the iron powder according to the presentinvention, an addition of at least one element selected from the groupconsisting of aluminum, magnesium, silicon, calcium, titanium, andzirconium each of which is very susceptible of combustion emittingenormous heat of oxidation is so made to the mother metal which may beiron or copper as to constitute a fragile alloy having a specificgravity which is not far from a commercial iron powder and then saidalloy subjected to pulverization is blended with said iron powder. Dueto its fragility said alloy is prone to an easy and inexpensivepulverization. The uniform mixture comprising said alloy powder and acommercial iron powder is less susceptible of oxidation as compared withaluminum powder so that the oxidation heat is given direct to thecutting surface of the objective resulting in increased efliciency ofthe gas'cutting operation. The unique iron powder employed for thegas-cutting pur- I pose according to the invention is prepared by somaking an addition to a base metal which may be iron or copper 2,967,767Patented Jan. 10, 1961 ice of at least one element selected from thegroup consisting of aluminum, magnesium, silicon, calcium, titanium, andzirconium as to produce a fragile alloy which is then thoroughly mixedwith a commercial iron powder. The total quantity of the alloyingelements appropriate for the addition to the base metal ranges in Weightfrom 10% to 60% of the base metal within which range the alloy producedis subject to pulverization at low costs.

In addition, thorough mixing of said alloy with the commercial ironpowder is made feasible because of the similarity in the specificgravities and thus in practice the amount ,of said alloy is optionallydetermined in relation to the specific objective which is to besubjected to gas-cutting.

However, in case the addition of said alloy to the base metal exceeds60%, the difference in the specific gravities of said alloy between thecommercial iron powder increases and the pulverization capacity of saidalloy decreases so that difficulties will be encountered in obtaining auniform mixture of these two constituents. On the other hand, if theaddition is short of 10%, the resulting alloy will become ductile losingthe properties of fragility and disintegration, so that the uniformmixture will be diflicult to obtain without a sacrifice in increasinglyexpensive pulverization of said alloy, and thus the advantages expectedby the addition of the alloying element are offset.

The alloy powder contained in the iron powder according to the inventionis not subject to instant combustion when exposed to oxidizing flame butis susceptible of rapid combustion only when brought into contact withthe oxyacetylene flame in the cutting region so that a large amount ofthe heat evolved can be given to the cutting surface of the objective.In addition, since the product of said combustion comprises iron oxideaccompanying at least one type of oxide from the group consisting of A10 CaO, SiO TiO Zr O and MgO, the molten slag thus produced as a resultof the combustion is lower in melting point and higher in fluidity thanthe slag comprising practically only iron oxide which is produced fromthe conventional iron powder. Consequently, clean cut cutting surfacesare acquired with higher efficiency in the gas-cutting with the ironpowder prepared in accordance with the present invention.

Some preferred embodiments of the invention will be described in detailwherein the examples given are for the purpose of illustrating preferredembodiments only and not for the purpose of limiting the same.

Example A.-Ir0n powder containing ferrous alloy (1) A soft steel isheated to melt at an elevated temperature for making an alloy containing45% aluminum. The alloy of this type is so fragile that it graduallybreaks up itself and accordingly the pulverization of the alloy iseasily carried out. Owing to the specific gravity of 5.6 whichapproximates that of commercial iron powder, said alloy can be uniformlymixed with commercial iron powder. With iron powder in accordance withthe invention comprising 30 parts of said alloy and 70 parts ofcommercial iron powder, clean cut gas-cutting is successfully carriedout at highest efliciency with respect to cast iron, stainless steel,copper, and nickel-alloy, etc. In fact, the iron powder in accordancewith the invention enables the speed of cutting a 30 mm. steel plate toincrease to 200 mm./min. from mm./min. with the conventional ironpowder.

(2) An alloy of iron-aluminum system containing 40% aluminum and 5%calcium or silicon is easily crushed. An iron powder in accordance withthe invention comprising 50 parts of such alloy and 50 parts ofcommercial iron powder enables non-ferrous metals such as nickel, Monelmetal, brass, and hastalloy to be easily cut.

(3) An iron powder in accordance with the invention comprising 30 partsof an alloy, which has been prepared by an addition of 40% aluminum and%titanium to a ferrousbase metal, and 70 parts of commercial iron powderrenders the suflicient clamping of copper or steel plate needless forthe successful lap gas-cutting of copper and stainless steel.

(4) In gas-cutting employing a conventional iron powder of 100 mm. castiron plate, the consumption of the iron powder was 5 kg. per meter ofthe cast iron plate cut at the cutting speed of 97.5 mm./min. With theunique iron powder according to the invention comprising 90 parts ofcommercial iron powder and parts of an alloy consisting of 55%commercial iron and 45% aluminum, the consumption of the new iron powderproved 3.5 kg. per meter of the cast iron plate cut at the cutting speedof 139.6 mm./min., thus showing approximately percent saving in the ironpowder consumption and 20 percent increase in the operation efliciency.

Example B.Ir0n powder containing cupreous alloy An alloy consisting of55% copper and 45 aluminum is very fragile and subject to easypulverizing. The iron powder comprising 90 parts of commercial ironpowder and 10 parts of said alloy in accordance with the invention makeswith ease the gas-cutting of such materials as stainless steel,cupreous-alloys, aluminum-cast iron, and

refractory bricks possible. With this new iron powder the ExampleC.-Gas-washing In employing the conventional iron powder for gaswashing5 mm. in depth of the surface of a steel plate having 280 mm. length and180 mm. width, it required 7 min. with the consumption of 1.4 kg. of theiron powder. In the case of the new iron powder in accordance with theinvention comprising 90 parts of commercial iron powder, 5 parts of analloy consisting of 55% iron and 45 aluminum, and 5 parts of an alloyconsisting of 65% iron and titanium, the consumption of the new ironpowder was 0.85 kg. requiring 5 /2 min, for carrying out the same work.Accordingly, the saving in the iron powder consumption was about with a20% increase in operating efficiency.

We claim:

An iron powder composition used for gas-cutting, gaswashing or gasscarfing purposes comprising a mixture of 1090% by weight of commercialiron powder and 10- 90% by weight of a powdered alloy comprising acopper base metal and at least one alloying element taken from a groupconsisting of aluminum, magnesium, silicon, calcium, titanium, andzirconium within the limit ranging from 10% to by weight of said basemetal.

References Cited in the file of this patent UNITED STATES PATENTS2,916,373 Freeman Dec. 8, 1959 FOREIGN PATENTS 160,479 Australia Jan.10, 1955

